Velsen Bed

Formal (Weerts 2003). First described by Bennema (1954).
Lithological description

Dark grey clay, firm, organic, laminated, commonly rooted with reed, locally abundant Peringia ulvae (partly in beds), intercalated silt, sand and organic detritus laminae. Upward increase in fine sand and decrease in organics.

Depositional setting

Infralittoral lagoonal, brackish; more saline to the top (Bennema 1954; Van Straaten 1957).

Definition of lower boundary

Commonly, conformable transition into peat (Basisveen Bed, Nieuwkoop Formation).

Definition of upper boundary

Unconformable, erosive contact with tidal sand (Naaldwijk Formation). Locally offshore, unconformable contact with marine sand (Southern Bight Formation) or mud (Urania Formation; Rijsdijk et al. 2005).

Thickness indication
Up to about 2.5 m.
Geographical distribution
Relatively small and scattered areas, primarily in the central-western Netherlands but also in the southwest and north (Vos & Van Kesteren 2000; Westerhoff et al. 2003).
Regional correlation
North Sea: Elbow Formation, mapped in conjunction with the British and Belgian Geological Surveys; UK: part of the British Coastal Deposits Group (McMillan et al. 2011); GER: part of Küstenholozän (Barckhausen et al. 1977; Preuss, 1979); BEL: part of the Calais Member, Vlaanderen Formation (Paepe & Baeteman 1979).
Holocene (Northgrippian).
Not yet determined.
Depth (thickness) AH:
Not yet determined.
Tentative location: Velsertunnel well section (Van Straaten 1957).
Not yet determined.
Depth (thickness) AH:
Not yet determined.
Tentative location: B19C0744, interval 25.80-28.25 m below land surface.
Origin of name
Named after the town of Velsen, west of Amsterdam.
Previous name(s)
Hydrobia Clay (Van Straaten (1957).
Reviewed by (date)
Wim Dubelaar (2018), Sytze van Heteren (2019).
Barckhausen, J., Preuss, H., Streif, H.-J. 1977. Ein lithologisches Ordnungsprinzip für das Küstenholozän und seine Darstellung in Form van Profiltypen. Geologisches Jahrbuch Reihe A 44, 45-77.
Bennema, J. 1954. Bodem- en zeespiegelbewegingen in het Nederlandse kustgebied. PhD Thesis, Wageningen University, 85 p.
McMillan, A.A., Hamblin, R.J.O., Merritt, J.W. 2011. A lithostratigraphical framework for onshore Quaternary and Neogene (Tertiary) superficial deposits of Great Britain and the Isle of Man. British Geological Survey Research Report, RR/10/03, 343 p.
Paepe, R., Baeteman, C. 1979. The Belgian coastal plain during the Quaternary. In: Oele, E., Schüttenhelm, R.T.E., Wiggers, A.J. (eds.), The Quaternary History of the North Sea. Acta Univ. Ups. Symp. Univ. Ups. Annum Quingentesimum Celebrantis: 2, Uppsala, 143-146.
Preuss, H. 1979, Die holozäne Entwicklung der Nordseeküste im Gebiet der östlichen Wesermarsch. Geologisches Jahrbuch Reihe A 53: 3-84.
Van Straaten, L.M.J.U. 1957. The Holocene deposits. The excavation at Velsen. Verhandelingen van het Koninklijk Nederlands Geologisch en Mijnbouwkundig Genootschap, 17 (2), 158-183.
Vos, P.C., Van Kesteren, W.P. 2000. The long-term evolution of intertidal mudflats in the Northern Netherlands during the Holocene; natural and anthropogenic processes. Continental Shelf Research 20, 1687-1710.
Westerhoff, W.E., Wong, Th.E., De Mulder, E.F.J. 2003. Opbouw van de ondergrond. Deel 3. In: De Mulder, E.F.J., Geluk, M.C., Ritsema, I., Westerhoff, W.E., Wong, Th.E. (eds.): De ondergrond van Nederland. Netherlands Institute of Applied Geosciences TNO - National Geological Survey, 249-352.
Cite as
TNO-GDN ([YEAR]). Velsen Bed. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from